This invention relates to motion controlling struts or vibration arrestors, and more particularly to a strut which may be connected between relatively movable elements, such as a steam pipe in a power producing station and adjacent supporting structure, to limit motion between the steam pipe and the structure, or any pair of relatively movable mechanical elements.
The prior art discloses a diverse assortment of approaches to various motion arresting problems. In particular, many attempts have been made in the prior art to arrest the motion between piping systems in thermal power plants and between various components of artillery pieces, for example, to limit the recoil of such apparatus. Some of these devices include an overhauling lead screw which is rotationally and axially fixed to one of the movable elements. Such lead screws are typically used to rotationally drive an axially-spring-centered braking device which, under normal circumstances, is centered axially between a pair of braking surfaces. These braking devices engage one of the braking surfaces as the motion parameter, typically acceleration, is increased.
The primary difficulty which has been encountered with devices of this type is the fact that the entire load which is to be supported by the motion arrestor must be borne by the overhauling threaded member, even under circumstances where the braking mechanism is engaged. This constraint severely limits the construction of the overhauling threaded member and also limits the load which may be supported by the motion arrestor.
While some attempts have been made to remove the overhauling threaded member from the main load bearing assembly, the resulting devices are typically extremely complex in construction and utilize a spring-centered braking arrangement which is itself subject to failure under mechanical stress.